AGU Fall Meeting 2012

Here are most of the proposed sessions related to astrobiology, in no particular order, as part of the next AGU Fall Meeting from December 3-7, 2012 on San Francisco, California. Deadline for abstract submissions is August 8, 2012 and the final program will be posted on September 28, 2012. We will highlight in this page on October some of the selected presentations or sessions from the final program that are related to planetary habitability.

Rapid environmental change can be used as a scientific bridge, relating astrobiology to earth, planetary, and space sciences in the study of how life may adapt through abrupt climate crises. Recent discoveries are inspiring the astrobiology community to re-examine its understanding of how rapidly planetary habitats can be redistributed and the variability of habitable zones around stars. Abstracts on the intertwined aspects of changing habitability, including the complex interactions among astronomical, geological, and climatic forces, on the Earth and beyond, are welcome.

Understanding planetary atmospheres and their evolution is one of the most challenging topics in planetary sciences. The competing influences of planetary geology, geochemistry, climate, atmospheric chemistry, and biology (on the Earth) need to be weighed. While geochemical and geological data provide constraints for the Earth, data from planetary mission and astronomical observations are necessary for other planets. Extrasolar planets have heightened interest in planetary atmospheres, for it is by analysis of their atmospheres that we will assess the characteristics and habitability of these objects. This session welcomes both observational and theoretical studies relevant to planetary atmospheres and their evolution in and out of our solar system.

The increasing number of discovered earth-like exoplanets raises questions about the habitability of these planets. The aim of this session is to discuss the potential for the origin and development of life on a sub-Earth to super-Earth sized terrestrial planetary body. What are the habitable conditions on such planets and how could the presence of life influence, for instance, the evolution of the atmosphere and the interior of a terrestrial planet?We invite contributions from all fields of planetary science including e.g., formation of planetary bodies, interior structure and dynamics, impacts, geological evidence on habitability, atmosphere, biogeochemical interactions, extremophiles, and mission concepts for exploration of planetary habitability.

Mass extinction events are among the few readily identifiable turning points in the evolution of life, and are key for understanding future biogeochemical responses to ocean deoxygenation and acidification. We invite contributions based on novel multi-proxy approaches and/or modeling that elucidate the timing and specific mechanisms leading to mass extinction during the Phanerozoic, and shed light on ecosystem resilience, and carbon and nutrient cycling. We welcome studies that provide information on the global nature of events, test existing post-extinction models, and provide new interpretations to reconcile fossil, isotopic and geochemical records.

Increasing evidence shows that the surface of glaciers and ice sheets harbour active microbial communities. These communities play an important role in the cycling of carbon and other elements within the cryosphere, and may be analogues for life on other icy planets, and may have been of fundamental importance to the evolution of life during Snowball Earth. In addition of providing labile sources of carbon and other nutrients to adjacent habitats typically starved for nutrients, microbial growth on the ice may also be important in decreasing the ice albedo thus accelerating melt. This session will bring biologists, biogeochemists and glaciologists together to understand the feedbacks between the ice habitat and microbial processes.

Permafrost represents one of the largest carbon (C) reservoirs on our planet. Permafrost thaw would enhance microbial decomposition of trapped organic matter, resulting in release of greenhouse gases into the atmosphere. Predicting the future of C emissions from thawing permafrost is critical to understand for climate models. However, microbial identities and their functional roles in permafrost are largely unknown. Therefore, there is a need to apply molecular tools to determine the functional roles of microbes in permafrost. This session aims to present current information obtained using molecular approaches about the role of microbes in processing organic C trapped in permafrost as it thaws and impacts of thaw on biogeochemical processes.

Serpentinization may generate an extensive deep habitat with metabolic engines drivenby H2, CH4, and/or complex organic compounds (e.g. Russell et al., 2010). The bioenergeticpotential produced by serpentinization of peridotite (in ophiolites or in the seabed) mayhave important implications for life on the Early Earth. Serpentine assemblages have beenidentified on the Martian surface, and are feasible in other planetary settings, bringingwide relevance to this work. We welcome reports investigating the potential for metabolicengines driven or influenced by serpentinization processes to support life, and encouragework that coordinates broad geochemical context with biological datasets (metagenomics,metatranscriptomics).

The Cassini spacecraft has made several very close flybys of Enceladus providing new insights into the nature and composition of the plume. Enceladus appears to have all the requirements for life: Energy, liquid water, organic material, nitrogen and other essential elements. Therefore, investigation of this body is especially promising and urgent. In this session, we will focus on the most recent observational, theoretical and modeling results on the chemistry, state and dynamics of Enceladus' jets and plumes, the moon's thermal and interior state, geologic activity, as well as its astrobiological potential. Submissions on new results from the recent Cassini flybys of Enceladus are encouraged.

A census of life beneath the Earth's surface is improving our knowledge of the diversity and physiology of organisms in this deep ecosystem. We invite presentations that explain bacterial, archaeal, eukaryal, and viral life in planetary-wide deep Earth settings where life ranges from abundant/active to sparse/surviving. Reports based on genomic, transcriptomic, proteomic, and lipidomic evidence; novel and single-cell cultivation; computational models; and new ways to visualize such life are encouraged. Explanations of the abiotic constraints on the diversity of subsurface life, the presence of keystone species, and recurrent themes related to life underground are especially welcome.

Understanding aspects of deep subseafloor biosphere and its relationship with energy and material fluxes transported by fluid flow beneath the seafloor have the potential to answer fundamental questions for evolution of life on Earth. Interdisciplinary research approaches in microbiology, geology, geochemistry, hydrology are important for this purpose. This session aims to provide an opportunity to discuss results and to integrate ideas raised from various disciplines during ongoing subseafloor focused programs and related studies.

This interdisciplinary session aims to bring together researchers studying the size, distribution, activity, and consequence of a microbial deep biosphere in the Earth's subsurface. Although the session will focus on the marine subsurface, including sedimentary and crustal environments, we encourage scientists involved in terrestrial deep biosphere studies to also participate. Scientists involved in recent ocean drilling program expeditions and other deep biosphere focused programs are encouraged to submit abstracts on any aspect of deep biosphere research, including biogeochemical, microbiological, and modeling approaches.

The Neoproterozoic Era (1000 to 542 MA) is a critical time in Earth history, encompassing the transition between the microbial world and the diverse multicellular animal and plant life of the Phanerozoic. Glaciation returned after a billion year absence, including Snowball events that certainly involved low latitude ice. Carbon isotopic excursions indicate major events in the carbon cycle, and there are indications of increased oxygenation, which probably paved the way for animal life. The linked climate and biogeochemical cycles of the Neoproterozoic were reviewed in Pierrehumbert et al (doi:10.1146/annurev-earth-040809-152447), and the proposed session will showcase the innovative new work that has appeared since.

The aim of this session is to provide a platform for knowledge transfer of findings and research strategies between environmental science and planetary exploration by seeding new ideas, insights, techniques, applications etc. harvested from one field into the other. Examples include miniaturized instruments developed for space missions that allow novel approaches to field work on Earth; the climates of Venus and Mars as extreme cases to test climate models for Earth; and the study of microbial communities in extreme environments on Earth as model systems for extraterrestrial life.

Phenology is a science that integrates climatology, ecosystem and land surface function, and community ecology. Despite persistent geographic patterns in life cycle events, predicting their timing remains a challenge. Alterations of plant and animal phenologies may be indicators of changes in seasonality (e.g., daylength, insolation, temperature/moisture thresholds or accumulations), species migrations or range shifts, ecosystem disturbances, extreme events, or climate change. How do such biogeophysical changes affect the timing of life cycle events and what are the ecological feedbacks between phenology, biogeophysical factors, disturbance, climate change, and species interactions?

The genetic record of extant microorganisms documents the interactions between life and the environment that it has inhabited throughout Earth history. This evolutionary link forms the basis of an emerging area of geobiological research that seeks to quantify the relationship between the distribution, diversity, and metabolic composition of microbial life and the characteristics of the environment that it inhabits. This session seeks research that integrates geochemical and molecular techniques in an effort to improve our understanding of the role of environment in shaping the distribution of biodiversity and the functions that it catalyzes.

The geologic record includes transient climate events of differing magnitudes that provide partial analogues to modern climate change, e.g., Paleogene hyperthermals and Mesozoic oceanic anoxic events. With increasingly sensitive geochemical techniques, state-of-the-art data acquisition, and exceptionally preserved fossil material we are at a pivotal time for addressing the sensitivity of past biota to climate change and quantifying thresholds in behaviour. We welcome contributions that utilize novel approaches, revisit older techniques or records, and integrate modern biological and paleontological observations to advance our understanding of past biotic responses.